Just over a year ago, Brian Lara won the toss for West Indies on a typically flat Antiguan wicket, and rattled along to a world-record 400 not out out of a gargantuan total of 751 for 5 declared. It remains to be seen whether Graeme Smith and AB de Villiers have that sort of landmark in mind, but in compiling an unbroken opening stand of 214 on the first day of the fourth Test, they ensured that South Africa maintained the momentum that has been steadily accumulating throughout the series.

The opening exchanges of the first Test, when West Indies posted a forbidding total of 543 for 5 declared in Guyana, now seem an eternity away. Ever since then, it has been South Africa making all the running. By the time a rain-interrupted day was brought to an early conclusion, Smith and de Villiers had reached, respectively, their third and second hundreds of the series, and in both cases they had come in consecutive matches.

South Africa's opening pair provide a microcosm of their team's progress in this series. Each time they have been asked to bat, their returns have just got better and better: 15 and 46 at Bourda, 117 at Port-of-Spain, 191 at Bridgetown, and now this. Both batsmen reached their hundreds moments before the rains rolled in - Smith with a straight drive down the ground off Chris Gayle, and de Villiers with a tickle to fine leg and a loud whoop of delight, one over later. It was his third Test century and Smith's 11th, and left West Indies hoping that Lara will be able to respond with his 29th - as and when his moment comes.

In 19 matches at the Recreation Ground, 19 innings have totalled more than 400 runs, and only seven have ended up fewer than 200, and by the close, it was not difficult to see which category this particular effort was destined for. Lara, gnashing his teeth in the slip cordon, could only ponder what might have been, because the writing was on the wall from the opening exchanges. Smith and de Villiers clobbered four fours in seven balls from the new-ball pair of Daren Powell and Tino Best, and after that they scarcely contemplated a backwards glance.

de Villiers, fresh from a career-best 178 at Bridgetown, was once again the early aggressor, peppering the cover boundary with a succession of gorgeous fours. His only alarm came on 83, when he popped a leading edge into no-man's land off Powell, and as he raced ahead in the run-scoring, Smith was content to take the back seat. Smith did, however, come perilously close to being run out on two occasions - once early in his innings, when Wavell Hinds missed the stumps with an underarm shy, and then - criminally - after lunch, when Narsingh Deonarine fumbled a simple effort with Smith floundering for his crease.

Best, who was back in the side for the first time since the tour of England last July, was showcasing a new and unnatural bowling action - a legacy of the back trouble that has plagued him since he burst onto the scene. There were shades of Brett Lee in his upright, poised arrival at the crease, but in conceding 37 runs from nine overs, he was a shadow of the former bundle of energy who was putting the wind up Nasser Hussain and Mark Butcher this time last year.

Disappointingly for West Indies, Best was unable to resume his partnership with Fidel Edwards, who has been rested amid fears about overdoing his workload so soon after his return from injury. Into his place came the 22-year-old debutant, Dwight Washington, who used his height to good effect in a decent first spell, but aside from one flashing carve over point from de Villiers, there was no threat of a breakthrough.

West Indies' only other change was the return of Deonarine, the Guyanese allrounder who stepped in during the contracts dispute and performed admirably in his one outing, at Bourda. He returned in place of Ryan Hinds, although it was South Africa who could boast the most significant recall - that of Shaun Pollock, who has recovered from an inflammation of his left ankle. He took his place in the side ahead of Andre Nel, who wrapped up the series with figures of 6 for 32 in the second innings at Bridgetown, but has been forced to sit this one out with a worrying recurrence of an old back problem.

St John's is no place for bad backs, however. With the likes of Jacques Kallis and Herschelle Gibbs tripping over themselves to get their chance on this featherbed, West Indies can expect another long, hot and draining day when play resumes half-an-hour early on Saturday morning. At this rate, their only respite is the rain.